The American National Standard for Arboricultural Operations—Safety Requirements (Z133) is a U.S. safety standard for the arboriculture industry, last published in 2017. Under Chair Dave Scharfenberger and Vice Chair Cary Shepherd, the Z133 Committee drafted revisions to refine the standard, improve safety outcomes, and keep pace with industry developments. The revisions underwent two public reviews and a committee vote to approve the draft for publication. 

As an ANSI-accredited standards developer, ISA must ensure that the Z133 Committee’s procedures and activities conform to ANSI's Essential Requirements, ensuring openness, balance, consensus, and due process. ISA, as secretariat, is subject to periodic ANSI compliance audits. 

Prior to publication approval, ISA underwent an ANSI special audit in 2024 and 2025, reviewing all procedural steps in the revision process. While much was carried out correctly, some procedural errors were identified. ANSI required ISA and the Z133 Committee to correct these steps and resubmit documentation. 

The Committee completed these corrections in late 2025, and ISA resubmitted documentation to ANSI by year's end. In the new year, ANSI shared that its auditor found no issues of non-compliance in the second special audit. 

A few procedural steps remain before publication. The audit findings must be formally reviewed by the Audit Subcommittee of the ANSI Executive Standards Council, which recommends next steps. ISA is currently awaiting their response, expected within several weeks to a month. Assuming a positive outcome, ISA will submit a final form—already prepared and ready to submit—to ANSI, providing evidence of procedural compliance. 

ANSI has confirmed it is realistic to expect approval of the Z133 draft as a revised American National Standard between March and July 2026. We are cautiously optimistic it may be on the sooner side of this timeline, but we cannot provide a more specific date. 

When we gain ANSI approval, the Z133-2026 will be made available in both English and Spanish as a free download for individual use from ISA’s web store. Print copies will be available for purchase through ISA and other authorized resellers. Companies and organizations that wish to print their own copies for training purposes or employee use may also inquire about a licensing option through ISA. Thank you for your patience as ISA and the Z133 Committee continue to navigate the lengthy audit process. Until the 2026 edition is published, the Z133-2017 remains in force. 

Meanwhile, the Z133 Committee remains active to ensure the standard keeps pace with industry developments and continues to improve safety outcomes. All meetings of the Z133 Committee are open to interested parties, and the next meeting is scheduled for 22 April 2026 in Baltimore, Maryland. Meeting information and registration can always be found on the Z133 website. 

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